[GreenKeys] Re: Just a few RTTY basic questions and a holiday thanks to all

[John Lawson]

On Thu, 25 Nov 2004 Wndrrt at cs.com wrote:

> Hello all and a Happy Thanksgiving.


Funny how we take all that time to stuff a turkey, and then un-stuff it 
while stuffing ourselves... hmmm...


>
> Jan Bogue KD6EMW here with a short update on the 19 set.  I did win the bid
> on a 1962 RTTY Hand Book on ebay.  Other information is being sent to me at
> this time.  Last week, I hooked up my temporary loop supply to the receive loop,
> and as I tapped the alligator clip on the positive contact screw on the
> terminal strip, the keys started hitting the platen in random order, so looks like
> my selector magnet works as well as the printer mechanisms.  This week I am
> going to try and trace out the send loop through the keyboard and the TD.
>

   Sounds promising. The machine should 'run open' in the absence of the 
loop current - it should just operate, perhaps printing whatever letter 
the code bails ended up on.  This should cease when you attach the loop 
supply, and the machine should be quiet, with just the motor running.

   The keyboard (the 'transmitter') has a set of contacts that are broken 
by the code set up as you type each key.  So these pair of wires goes in 
*series* with the typing unit (the 'reciever). Thus when you type on the 
keyboard, the current impulses are sent to the selctgor magnets and tghe 
typing unit (hopefully...) types that character and spaces over one space. 
This is called "Local" mode. It is possible to send material from the 
keyboard, while recieving different material on the typing unit, since 
they are in effect separatge devices sharing a common motor drive - 
however that would be pretty confusing....  this just illustrates that 
they are separate as far as wiring goes.

   I would suggest that you scare up a cheap 0 - 100 milliampere meter from 
somewhere and put it in the positive lead of your loop current supply - 
this will help you see that data is flowing, and also keep you from frying 
your selctor magnets - not a particularly fun thing to do, IMHO.  ;}




> A few questions:
>
> If my machine is geared for 60 wpm and 45.45 baud, what happens if the 19
> tries to copy 50 baud on Hamburg Metro Weather (taken from rtty.com frequency
> list)?
>
   You'll get Martian...   won't work... the data will try and overrun the 
Mod 19 - extra pulses will be recived instead of the 5-per-operation, and 
it'll print junk.


> Can the 19 be geared to handle short 75 baud contacts?
>
   No - if it's the tpical 19 set you'd tear it up trying to run that 
fast, AFAIK - I'm pretty sure tha machine can't respond that fast 
mechanically, and the resulting interference between parts would be 
noisily disastrous.


> It looks like the 19 is limited to copying Amateur Bulletins on 3620 W2QFR.
> Are there other frequencies where the baud is a civilized 45.45 for the old
> machines to work on?
>

   There are a few - I think others here might have pointers to better 
lists than I have...  but unencrypted 45-speed 5-level signals are getting 
relatively rare(er).  Keep tuned here for the RTTY net we're all trying to 
get up and going...  also you can try and copy the W1AW RTTY transmissions 
from the ARRL - the scedule is on thier website, and each issue of QST 
magazine.


> Do some computer programs and modern, painfully quiet, RTTY setups without
> moving machine parts equipped to communicate with the old machines?  New on one
> end of the QSO and antique on the other end?
>

   Yes - as long as your baud rates and codes match, it matters not what is 
sending/recieving - If my laptop running TrueTTY sends a QSO to your Mod 
19, 45.45 speed and Baudot code, then we should be able to print each 
other FB, all else being equal. Done this many times, and I also use my 
computer to test and tune up my Mod 19, Mod 26, Mod 28(s) and Mod 35.
There is a freeware program available, called "Heavy Metal" which will 
allow you to translate files on your computer to 45-speed Baudot to drive 
your Iron, for example you could set it up to download AP or CNN feeds, 
decode to text, then squirt the text out to a loop converter - if your Mod 
19 was set up for autostart, then at intervals it would just turn itself 
on, clack out a page or two of News, and then shut down.  This is Tre 
Cool, as they say.


> All basic stuff, but when you are in first grade you have to start at the
> bottom with the basics.

  We've all been right here - I learn Stuff all the time from this list, 
and I got my first TTY (A Mod 14 typing reperf) when I was 14, about a 
hundred years ago...  :} (actually 1966)


>
> And now for a quick Thanksgiving note:
>
> I have only been a Ham for three months, and when I think back I cannot
> remember a time when I have come in contact with  so many helpful and kind people
> in such a short period of time. This includes those in related fields as well.
> And the attitude is contageous.  I find myself passing the attitude on in my
> daily dealings with others at my job.  Thanks to all.
>

   What Ham Radio oughyts should be, IMHO...  thank you, too!



> Two more questions:
>
> Are the old machines limited to talking only to their own generation?
>

  No, as above - as long as the basic codeset (Baudot, Murray, 
ITC-whatever) and the baud rate match, it does not matter what physical 
device sends or recieves.


> Can my Hallicrafters Model SX99 or my Hallicrafters Sky Champion be used as a
> source for a RTTY signal?  Dose the signal have to come from a SSB  lower
> band radio?

  You will most likely have a problem with drift - the BFOs need to be 
rock-stable or you're forever chasing the signal...  without having a 
tuning indicator you'd find it problematic. If the SX99 was warmed up well 
and in a draft-free room, you might have better luck with it.

  What Terminal Unit (TU) are you using? You need something to take the 
tones from the radio and make loop pulses out of them - I don't remember 
you mentioning that, but if you don't have one, that's the next Thing 
you'll need to get.


  Cheers

John  KB6SCO